Ducati Monster Forum

I've seen threads like this http://www.ducatimonsterforum.org/index.php?topic=57299.0 (http://www.ducatimonsterforum.org/index.php?topic=57299.0) and thought", I can do that" but I don't really know WHY the breather box is there, and what the concerns are for removing or relocating it.

I bought an S4R shock to go in the duc, and looks like I need to relocate this to make it fit. Honestly, I am very wheelie-prone. It's rare I go for a ride, even to work, that the front wheel stays on the ground 100% of the time. Is this a concern for breather boxes?

Help school me, please!

Someone else will know more, but I'm in the same boat, and from my reading, it's best to have the hose run as high and far forward as you can get it. With an airbox still installed thats a problem however. I know http://www.ducati-upnorth.com/tech/breather.php (http://www.ducati-upnorth.com/tech/breather.php) has some extra technical information albeit oriented more towards 4v bikes.

As high and as far back as possible.


IF you pull wheeiie that much, you have other things to worry. (such as constantly blown fork seals, damaged steering head bearings, etc. Watch Keith Code's Twist of the wrist 2 video. It shows front end landing down from wheelie, in slow motion. After seeing front tire squashed, forks bottoming out, and thinking all the damage you will cause to the front end, you don't want to pull the wheelie anymore.)

 Killjoy!

Oh, I thought it was forward because of wheelie kids. I assume the far BACk is so if it dumps everywhere its not on your tire?

The breather box is there so combustion gasses that pass the piston rings and enter the crankcase have someplace to hang out before going into the engine to be re-burned instead of allowing the vapors to enter the atmosphere. 

Yes, high and back.  Also, not too much oil on the filter.

I agree with S21FOLGORE about the wheelies.

Does it increase horsepower? or lower it? I have seen both statements.

So, the gasses will just vent to the atmosphere instead of recycling?

Will oil come out of it?

 Or it MIGHT make your engine seize!

or not.............

Just to be clear, I'm not looking for extra power. Can't keep the wheel on the ground as it is.  But is it honestly a threat to the engine to remove it?  So many people seem to be doing it, that I am surprised to hear that. If it's just for offgassing, how can removing it be so treacherous?

Think of it as a PCV valve on a car in stock configuration. Sort of. I did mine several thousand miles ago and I haven't had a bit of trouble out of it. I got a Nichols breather that at the time had a better reed valve in it compared to the stock piece and most aftermarket pieces.

Horsepower gain or loss will be minimal on your 2 valver.  Probably no gain or loss if you are running an open air box. 

Would it be possible to just move it further back under the tail, just adding more tubing, away from where the shock reservoir would be?

Before you spend more energy on the breather topic, I fear the S4R shock won't fit your frame (if it's a smaller bike). Anyway, if it does - the breather box won't be in the way and then I don't see a functional reason to remove it...

It works, for sure. several people have done it. but it's a pain. just wondering if i shouldn't stick this shock right back on ebay and suck up the $600 price tag and get an ohlins that fits without modifying...

Just for some clarity on the 'Damage' concern. In a car, the seals of the car(valve cover etc) can be negatively effected by a tampered with PCV system. In fact on many street rods, weekend warriors etc, guys will run the breather into the exhaust pipe to have exhaust gas pull the blowby out of the crankcase. Since so many are putting breathers on their monsters, and motorcycles are better sealed to begin with, this doesn't seem to be a problem. But you'll have to trust others with more Duc experience. My experience with modified cars has been that a tampered with PCV will eventually cause some leakage. That is the worst of the damage that can be done in a worst case scenario, besides tuning issues and MIL(cel) on closed loop EFI vehicles.

Well, in light of all the information here, just for shits and giggles, does anyone see a problem with;
1. Running an open breather (like this - http://www.cncracing.us/prodDetail.asp?ID=92 (http://www.cncracing.us/prodDetail.asp?ID=92))
2. And then fitting an automotive PCV valve (like this - http://www.framcatalog.com/PartDetail.aspx?b=F&pn=FV368 (http://www.framcatalog.com/PartDetail.aspx?b=F&pn=FV368)) high up in the standard system (ie cut into the breather hose about 2-3"  below where it joins into the airbox).

This would leave all the standard piping and catch pan (breather box) in situ and increase the available volume of the crankcase, yeah?

Please advise as I'm probably going to give this a go unless I get told not to  ;)

Just quitcha hand wringing and take the damn thing off already.  ;) :P Your bike will be fine.

http://www.ducatisuite.com/emissions.html (http://www.ducatisuite.com/emissions.html)

I wonder if this guy has any 19mm, some of these look super trick;

http://www.ebay.com/sch/i.html?_odkw=crankcase+filter+19mm+REUSABLE&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0&_nkw=crankcase+filter+REUSABLE&_sacat=0 (http://www.ebay.com/sch/i.html?_odkw=crankcase+filter+19mm+REUSABLE&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0&_nkw=crankcase+filter+REUSABLE&_sacat=0)

edit: don't listen to me. I'm one of those jackasses that put the aesthetics of my bike ahead of the utilitarian aspect provided there is nothing clearly detrimental about it. That being said, this is one of those subjects I stayed up into the wee hours reading Ducati forums and tech articles on, and in the end, the jury is still out on it,but the edge goes to keeping the stock setup intact. In other words, your bike is better off with the stock setup, but the sky isn't going to fall if you don't.

this is a pretty good; "final word" on the subject:

http://www.ducati-upnorth.com/tech/breather.php (http://www.ducati-upnorth.com/tech/breather.php)

I had no choice, because I cut up my airbox when I swapped in a 900ss engine and pod filters. The airbox ventilation was out of the question for me.

I just like to be different. I try to do things once but usually they get done two or three times and things gradually progress from stock to half home modified to full home modified. ;)

Thanks for the second opinion.